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Thread: OBDII drive cycle explained/smogging

  1. #1
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    OBDII drive cycle explained/smogging

    Howdy gents. So I went to go to DEQ this morning (our smog testing) and the X5 was running a P0455 code for the "Evaporative Emissions Control System." Of course they fail me for this, at least you don't pay unless you pass. So whatever I take it to the stealership cause it's close, they reset the code and the service clown tells me it was probably just a loose gas cap or something. So I tell him thanks I'm going right back to DEQ. Well he says I need to run it for a couple of days for the OBDII system to get all it's tests done before it can be read again by DEQ. So I'm thinking "aw hell naw" there's got to be a way to put the car through these tests manually without having to wait a few days. Turns out there is, and the purpose of this thread is to share this information. It's not easy to do all this during Friday rush hour like I did, but it worked beautifully and in about 20 minutes I went back to DEQ and passed. Hope this can help someone else.

    p.s. I didn't do the last deceleration and everything was still fine.




    OBD-II Driving Cycle
    If you have a 96 or newer vehicle you have the OBD-II diagnostic system. This system is constantly monitoring the sensors and solenoids on the engine. If you have replaced the battery, disconnected the battery or cleared the codes after making a repair you will need to do what is called a "Driving Cycle". This will perform a diagnostic on all the systems the computer monitors. This cycle can be done in under fifteen minutes.

    To perform an OBDII Driving cycle do the following:

    1. Cold Start
    In order to be classified as a cold start the engine coolant temperature must be below 50C (122F) and within 6C (11F) of the ambient air temperature at startup. Do not leave the key on prior to the cold start or the heated oxygen sensor diagnostic may not run.

    2. Idle
    The engine must be run for two and a half minutes with the air conditioner on maximum and rear defroster on. The more electrical load you can apply the better. This will test the O2 heater, Passive Air, Purge "No Flow", Misfire and if closed loop is achieved, Fuel Trim.

    3. Accelerate
    Turn off the air conditioner and all the other loads and apply half throttle until 88km/hr (55mph) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed.

    4. Hold Steady Speed
    Hold a steady speed of 88km/hr (55mph) for 3 minutes. During this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.

    5. Decelerate
    Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 32km/hr (20 mph). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.

    6. Accelerate
    Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will perform the same diagnostics as in step 3.

    7. Hold Steady Speed
    Hold a steady speed of 88km/hr (55mph) for five minutes. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst.

    8. Decelerate
    This will perform the same diagnostics as in step 5. Again, don't press the clutch or brakes or shift gears.

  2. #2
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    All I did to mine was drive it normally for about a 1/2 hour.

    I wouldn't have enough memory to do that procedure, and don't want to be reading while driving. Glad it worked for you. Is that something you got from a dealer, or something you came up with yourself?

  3. #3
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    No I found it after googling for a while. I've heard people say just driving for a certain amount of time works, but I wanted to make sure it was ready. Also handy I guess if you clear a code and want to test car again right away.

  4. #4
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    You did not mention the evaporative emmissions monitor. On most cars this requires that the fuel level be between 1/4 and 3/4. You also did not mention what year your car was. Older cars are allowed more incomplete monitors.

    My car had an evaporative emmissions large leak for about two years before I replaced the gas vapor expansion tank. Yes, a loose gas cap can also cause it. My car could pass inspection because there was a window of oportunity between the other monitors completeing and the CEL comming on due to the leak.

    Please re-post if your CEL comes on in the next couple of weeks.

  5. #5
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    UPDATE: After a week still no CEL on.

  6. #6
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    Exclamation obd drive cycle

    my 2002 325xi is failing deq as well due to catalyst not bieng ready as well as 2 other things not bieng ready, Not sure if the drive cycle posted can work for me because i dont live in an area that allows me to be able to do 55 right away. So i was wondering if i could just drive my car for more than a half hour straight and where i need to drive it. the deq guy said to just drive it on the freeway for awhile then take it downtown for awhile and that i may need to do this for a few days. very confused what do i do?

  7. #7
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    I don't think you need to accelerate to 55 right away. But you do need to do it before turning the key off. I found that my daily commute did not include a "drive cycle". I had to alter my route.

  8. #8
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    Thank you, thank you, thank you for posting this! I just moved to TN that requires e-checks (never had to deal with before). Take my z4 in and after spending way too much time waiting, I fail. I rarely drive the z4 as I have a company car, so it's just a weekend/nice weather toy. Apparently as a result of that and my 800 lb right foot, I had not completed a drive cycle and failed because it was 'not ready' for fuel, 02, and cat. Call the stealership for advisement of the drive cycle and was told drive at least 100 miles for 7 days. Ummm no....I'm not wasting time, gas and miles and knew there had to be more of a science to the OBD and was not willing to risk spending more time at the echeck just to fail again. Attempting the above this evening from cold start, keeping my fingers crossed that it works and I can pass tomorrow (considering my tags expire in 2 days!!). Thanks again!!

  9. #9
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    Exclamation failing deq

    This question is a continuation of my previous problem. So i am not passing Oregon deq because the paper says that my catalyst is unready, my O2 sensor is unready and the evaporative is unready. Help! I have a code reader, plugged it in and scanned. The codes i got were misfires from cylinders 1 through 6. When the engine light came on i figured it needed a tune up. that was before i got the code reader tool. I replaced the spark splugs. with bosch plugs. didn't work. still failed deq. replaced the front 2 O2 sensors. didnt work. still failed deq. now i just plain don't know. I cant afford the stealership!!! Is Bosch a good repair shop to go to or can someone reading this give me some suggestions. HELP!

  10. #10
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    Driving Cycle

    Thanks Sean,

    My car was rejected because it wasn't ready.
    Thanks for posting the driving cycle.

    I appreciate it , Sam

  11. #11
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    I have tried this driving cycle and my car still shows not ready. Do we have to do all of that in the exact order?

    Sold95 M3 - Ground Control Track/School coilovers | Eibach Sway bars | Powerdyne supercharger | Dinan Exhaust | WAR Chip

  12. #12
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    My 2001 525i won't reset the 2AC monitor unless the temperature outside is less than 60 F. In S. Cal in summer this is usually not possible, but it can be tricked into resetting if you put a cup of ice water around the OAT sensor and idle it for a while stationary.

  13. #13
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    Exact order is not necessary.. It is a good idea to get an OBDII scanner - a cheap one like the Autel MS300 is good enough- so you can find out just what monitor is not clearing. Then you will have a better idea how to proceed. I suppose your problem is long gone by now, but other people may need to know.

  14. #14
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    2004 545i with sport package 108k miles. I had replaced a dead battery just before heading to the emissions test last friday, it was showing not ready when he hooked up to the OBDII port, the guy told me to do a drive cycle and bring it back monday for another try. the drive cycle worked, car passed with no problems, i did it at night on a freeway, used cruise control , the right lane and flashers for safety. i did four cycles just to make sure, probably overkill but better safe than not going thru again, all in all i put about 70 miles on the car as well as another 70 miles just with everyday normal driving around.

  15. #15
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    As a note, doing the 55mph segment made my O2 and catalytic sensors ready. Another doc I read you can not go over 60mph or rev over 3k during the process. Specifically I did the cold start (run for 3 minutes) then drove to the highway and did 55mph for 15 minutes, which is what the other readiness document said, never going above 60mph or 3k rpm.



    The segments can apparently be done in any order, as long as you cold-start.

    Edit: here is the correct link with the wayback machine https://web.archive.org/web/20120601...cs/OBDproc.pdf
    Last edited by shogun; 08-07-2017 at 11:39 PM. Reason: link corrected

  16. #16
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    the most common monitor that is difficult to set is cat monitor. the drive cycle that has worked is. don't go past 3,000 rpm in any gear, 40-60 mph, have coasting points for a few moments. for instance I get on the freeway, the on ramp is up hill, at the top of the free way hill I try to coast down, as much as I can, then resume the 40-60 mph. then I hit another small freeway hill, coast down the other side, then up the next one and coast down the other side.

  17. #17
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    I cleared all the codes on my 01 Z3 3.0 stick.
    Now I need to get it smogged/emissions tested.
    I've done 80 miles trying to reset the computer & everything is good to go apart from the CAT not being ready.
    Anybody have any ideas? More miles? Different speeds? Seafoam?


    I just did seafood and it's still not reset after another 10 miles.

    Looking at this drive cycle the only thing I haven't done is 55 for 5 minutes...I was between 65/80 for probably 15 minutes.

    I'll put some more miles on it tomorrow.

  18. #18
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    I just set an e46 m3 cat mon and an e38 740. To set cat mon and oxygen mon you must drive for at least 20 mins no stopping, no braking, 40-50 mph, no quick accelleration, don't go over 3,000 rpm. If you have any pending faults in the dme that have no turned on the check engine light yet that will stop the setting process. When I Have a problem car I will drive it for for more like 25 mins or more. The m3 had been driven over 100 miles and it would not set. My first drive I tried my short drive of 10-15 mns and it didn't work. Then tried again, the long drive always works for me. i have set many cat mon with the longer drive.

  19. #19
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    I dont think pending codes interrupt the drive cycle procedure. They will either remain pending or throw a CEL. If they remain pending its ok...

  20. #20
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    I agree with BimmerBreaker,
    Pending codes don't interrupt a drive cycle,
    they no longer are pending after three drive cycles,
    but confirmed,thereby triggering a dash warning.
    Last edited by MIKYZZ4; 05-13-2017 at 02:10 PM.

  21. #21
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    Quote Originally Posted by jclausen View Post
    If you have any pending faults in the dme that have not turned on the check engine light yet that will stop the setting process. When I Have a problem car I will drive it for for more like 25 mins or more. The m3 had been driven over 100 miles and it would not set. My first drive I tried my short drive of 10-15 mns and it didn't work. Then tried again, the long drive always works for me. i have set many cat mon with the longer drive.
    Hate to burst anyone's bubble here, but jclausen is 100% right! Just did an engine swap on my 2000 528i. Clearing all the pending codes (to get smogged in S. Ca) I could get 7 out of 8 readiness completed. All but Cat mon would be ready. No matter what I did, I couldn't get pass the last and final readiness. So I took it to the guy who did the engine swap and said "I need to get this smogged!" In which he replied, you have a P1622 error code PENDING, and I''ll put in a new thermostat and housing, but once I do, you're going to need to clear the code because the cat mon will NEVER become ready until you do. As long as you have an error code pending or showing, the CAT mon will never become ready... This guy does NOTHING but bimmers..

    In doing so, I am once again at 7 out of 8 readiness, this Cat Mon is a bitch to complete, BUT I do not have an error code pending anymore. So I'm going to try the "long drive" and hope it works.. Any special advice here jclausen? Being as you said you've done this (set many cat mon) with the longer drive...

  22. #22
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    Yea I am right I have been setting fucking monitors for my customers for years and pending faults that are set during the drive cycle will stop the process and the check engine light does not come on. So remember to check for pending faults when setting monitors and if your thermostat is stuck open that may not allow certain monitors. Did you know that secondary air faults are set thru how the oxygen sensor reads on cold start up.

  23. #23
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    You must clear pending faults also.

  24. #24
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    I know this thread is old but does anybody know if the driving cycle is same for 2015 3 series? I drove over 600 miles and one monitor is not ready, not sure witch one but looking at the OBD2 its "EG" flashing meaning its not ready.

  25. #25
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    i know this is an old thread, but thought I would give you my experience, and fix for Catalytic not monitoring.

    First, this was a long process. Originally, after purchasing my 2000 528i BMW, I blew the head gasket, because of a radiator fault and the car overheating. Replaced, yet that went bad after 6 months because a head bolt loosened. After much blah blah blah, I replaced the engine. Yet, I used the original Catalytic Converters. Fast forward, my Cat would not monitor. Numerous trips to BMW, resetting the computer, and them driving the vehicle to see if they could get it reset,, no success. Replaced the Cats with aftermarket cats (which needed a little customization to make them fit) Drove the DRIVE CYCLE at least 30 times, yet the Cats would not monitor. I was planning on refurbishing this car, but wouldn't unless I could get it to smog (BTW, got a years extension on my CA smog, which turned into two years because they sent me the second year tags without requiring a smog check) Now, heading to the 3rd year and smog is required in November. Last January, I felt lucky one day and stopped by my mechanic to check the OBDII monitors. to my surprise, they all passed!!!! So, knowing that the new CATS were working, I had my BMW painted, with new interior and new stereo system ,,, Fast forward to present. Took my vehicle to my mechanic to smog, and the CAT did not pass. DAMN !!!! Looking back at what was different, after the monitors passed in January, the battery was disconnected in order to install the new stereo system. I've been driving for the past 7 months, with the CAT not monitoring. My usual driving pattern is around town, with very little freeway driving. Thinking about what I did differently when it passed in January, was I drove from Northern CA to So. CA... So, again , I planned to start driving the DRIVE CYCLE, but instead, I purchased a Bosch monitor, so I could check it myself. Yesterday, i drove just over 100 freeway miles and when I stopped. I checked the monitors and ALL passed!!!! I did not do any special driving, 55 miles and hour for 15 minutes ETC,,, I just drove. So,, if anyone reading this is having this problem ,, this is what I found out:
    1- If you blow a head gasket, there is a likelihood the CATS will not monitor, because the coolant gets into the cats and ruins them.
    2- Regular driving will reset most of your codes for smog
    3- CAT code reset apparently needs prolonged driving conditions to reset the code. (Drive cycle, driving 55 MPH for 15 minutes did not reset the CAT)

    Hope this made sense....

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